FIRST PRINCIPLES STUDIES OF ELECTRONICALLY EXCITED SPECIES

Abstract

The study of electronically excited states is required for insights into ultrafast events such as the radiationless decay in DNA. In this work, the characterisation of a molecule’s excited state and the various processes by which the excited state can relax and return to the ground state are examined using computational methods. First, time-dependent density functional theory (TD-DFT) with various exchange-correlation (XC) functionals were used to examine various photophysical properties of <I>syn</I> bimane derivatives, including their absorption, emission, solvatochromism, and fluorescence lifetimes. Next, TD-DFT is used in conjunction with non-empirically tuned range-separated XC functionals to model fluorescence lifetimes under different approximations for the emitting molecule. Intersystem crossing in the bimanes is then examined to explain the difference between the photophysical behaviour of <I>syn</I> and <I>anti</I> bimanes. Finally, a bimane dimer system is used as a model towards the study of the energy transfer process after electronic excitation